Featured Research

from universities, journals, and other organizations

Crabs Not Only Suffer Pain, But Retain Memory Of It

Date:
March 28, 2009
Source:
Queen's University Belfast
Summary:
New research has shown that crabs not only suffer pain but that they retain a memory of it. The study looked at the reactions of hermit crabs to small electric shocks.

This is a hermit crab.
Credit: Professor Bob Elwood

New research published by a Queen's University Belfast academic has shown that crabs not only suffer pain but that they retain a memory of it.

The study, which looked at the reactions of hermit crabs to small electric shocks, was carried out by Professor Bob Elwood and Mirjam Appel from the School of Biological Sciences at Queen's and has been published in the journal Animal Behaviour.

Professor Elwood, who previously carried out a study showing that prawns endure pain, said his research highlighted the need to investigate how crustaceans used in food industries are treated.

Hermit crabs have no shell of their own so inhabit other structures, usually empty mollusc shells.

Wires were attached to shells to deliver the small shocks to the abdomen of the some of the crabs within the shells.

The only crabs to get out of their shells were those which had received shocks, indicating that the experience is unpleasant for them. This shows that central neuronal processing occurs rather than the response merely being a reflex.

Hermit crabs are known to prefer some species of shells more strongly than others and it was found that that they were more likely to come out of the shells they least preferred.

The main aim of the experiment, however, was to deliver a shock just under the threshold that causes crabs to move out of the shell, to see what happened when a new shell was then offered.

Crabs that had been shocked but had remained in their shell appeared to remember the experience of the shock because they quickly moved towards the new shell, investigated it briefly and were more likely to change to the new shell compared to those that had not been shocked.

Professor Elwood said: "There has been a long debate about whether crustaceans including crabs, prawns and lobsters feel pain.

"We know from previous research that they can detect harmful stimuli and withdraw from the source of the stimuli but that could be a simple reflex without the inner 'feeling' of unpleasantness that we associate with pain.

"This research demonstrates that it is not a simple reflex but that crabs trade-off their need for a quality shell with the need to avoid the harmful stimulus.

"Such trade-offs are seen in vertebrates in which the response to pain is controlled with respect to other requirements.

"Humans, for example, may hold on a hot plate that contains food whereas they may drop an empty plate, showing that we take into account differing motivational requirements when responding to pain.

"Trade-offs of this type have not been previously demonstrated in crustaceans. The results are consistent with the idea of pain being experienced by these animals."

Previous work at Queen's University found that prawns show prolonged rubbing when an antenna was treated with weak acetic acid but this rubbing was reduced by local anaesthetic.

The findings are both studies are consistent with observations of pain in mammals.

But Professor Elwood says that in contrast to mammals, little protection is given to the millions of crustaceans that are used in the fishing and food industries each day.

He added: "More research is needed in this area where a potentially very large problem is being ignored.

"Legislation to protect crustaceans has been proposed but it is likely to cover only scientific research.

"Millions of crustacean are caught or reared in aquaculture for the food industry.

"There is no protection for these animals (with the possible exception of certain states in Australia) as the presumption is that they cannot experience pain.

"With vertebrates we are asked to err on the side of caution and I believe this is the approach to take with these crustaceans."


Story Source:

The above story is based on materials provided by Queen's University Belfast. Note: Materials may be edited for content and length.


Journal Reference:

  1. Robert W. Elwood, Mirjam Appel. Pain experience in hermit crabs? Animal Behaviour, 2009; DOI: 10.1016/j.anbehav.2009.01.028

Cite This Page:

Queen's University Belfast. "Crabs Not Only Suffer Pain, But Retain Memory Of It." ScienceDaily. ScienceDaily, 28 March 2009. <www.sciencedaily.com/releases/2009/03/090327072759.htm>.
Queen's University Belfast. (2009, March 28). Crabs Not Only Suffer Pain, But Retain Memory Of It. ScienceDaily. Retrieved August 29, 2014 from www.sciencedaily.com/releases/2009/03/090327072759.htm
Queen's University Belfast. "Crabs Not Only Suffer Pain, But Retain Memory Of It." ScienceDaily. www.sciencedaily.com/releases/2009/03/090327072759.htm (accessed August 29, 2014).

Share This




More Plants & Animals News

Friday, August 29, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Killer Amoeba Found in Louisiana Water System

Killer Amoeba Found in Louisiana Water System

AP (Aug. 28, 2014) State health officials say testing has confirmed the presence of a killer amoeba in a water system serving three St. John the Baptist Parish towns. (Aug. 28) Video provided by AP
Powered by NewsLook.com
Raw: Australian Sheep Gets Long Overdue Haircut

Raw: Australian Sheep Gets Long Overdue Haircut

AP (Aug. 28, 2014) Hoping to break the record for world's wooliest, Shaun the sheep came up 10 pounds shy with his fleece weighing over 50 pounds after being shorn for the first time in years. (Aug. 28) Video provided by AP
Powered by NewsLook.com
Minds Blown: Scientists Develop Fish That Walk On Land

Minds Blown: Scientists Develop Fish That Walk On Land

Newsy (Aug. 28, 2014) Canadian scientists looking into the very first land animals took a fish out of water and forced it to walk. Video provided by Newsy
Powered by NewsLook.com
Fake Dogs Scare Real Geese from Wis. Park

Fake Dogs Scare Real Geese from Wis. Park

AP (Aug. 28, 2014) Parks officials in Stevens Point, Wisconsin had a fowl problem. Canadian Geese were making a mess of a park, so officials enlisted cardboard versions of man's best friend. (Aug. 28) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins